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12
MAINTENANCE AND REPAIR INSTRUCTIONS
WARNING: To avoid serious personal injury, always
turn your unit off and allow it to cool before you clean or
service it.
10. If the clearance is not within specification:
a. Turn the adjusting nut using a 5/16 inch (8 mm) wrench or
nut driver (Fig. 40).
• To increase clearance, turn the adjusting nut
counterclockwise.
• To decrease clearance, turn the adjusting nut clockwise.
b. Recheck both clearances, and adjust as necessary.
11. Reinstall the rocker arm cover using a new gasket. Torque
the screw to 20–30 in•lb (2.2–3.4 N•m).
12. Reinstall the engine cover. Check alignment of the cover
before tightening the screws. Tighten screws.
13. Reinstall the muffler cover. Slip the rear tab on the muffler
cover into the engine cover rear slot. Then slide the remaining
slots into the tabs until they snap into place (Fig. 31).
14. Check the spark plug and reinstall. See Replacing the
Spark Plug.
15. Replace the spark plug wire.
REPLACING THE SPARK PLUG
Use a replacement part number 791-180852B spark plug. The
correct air gap is 0.025 in. (0.635 mm.). Remove the plug after
every 25 hours of operation and check its condition.
1. Stop the engine and allow it to cool. Grasp the plug wire
firmly and pull the cap from the spark plug.
2. Clean dirt from around the spark
plug. Remove the spark plug
from the cylinder head by turning
a 5/8 in. socket
counterclockwise.
3. Replace cracked, fouled or dirty
spark plug. Set the air gap at 0.025
in. (0.635 mm.) using a feeler
gauge (Fig. 41).
4. Install a correctly-gapped spark
plug in the cylinder head. Turn the
Adjusting Nuts
Feeler Gauge
Rocker Arms
Fig. 39
INTAKE
EXHAUST
Fig. 40
Feeler Gauge
Exhaust
Adjusting Nut
Exhaust
Rocker Arm
Exhaust
Clearance:
.003-.006 in.
(.076-0.152 mm)
Exhaust Valve Stem
Intake Valve
Stem
Intake Clearance:
.003–.006 in.
(.076–0.152 mm)
5/8 in. socket clockwise until snug.
If using a torque wrench torque to: 110-120 in.•lb. (12.3-13.5
N•m)
Do not over tighten.
SPARK ARRESTOR MAINTENANCE
1. Remove the muffler cover. See Rocker Arm Clearance.
2. With a flat blade screwdriver or Torx T-20 bit, remove the
screw attaching the spark arrestor cover to the muffler (Fig. 42).
3. Pull the tab on the spark arrestor cover out of the muffler.
Remove the spark arrestor cover.
4. Remove the spark arrestor screen from the spark arrestor
cover.
5. Clean the spark arrestor screen with a wire brush or replace it.
6. Reinstall the spark arrestor screen, spark arrestor cover
and screw.
CLEANING
Use a small brush to clean off the outside of the unit. Do not
use strong detergents. Household cleaners that contain
aromatic oils such as pine and lemon, and solvents such as
kerosene, can damage plastic housing or handle. Wipe off any
moisture with a soft cloth.
STORAGE
• Never store the unit with fuel in the tank where fumes may
reach an open flame or spark.
• Allow the engine to cool before storing.
• Lock up the unit to prevent unauthorized use or damage.
• Store the unit in a dry, well-ventilated area.
• Store the unit out of the reach of children.
LONG TERM STORAGE
1. Drain all gasoline from the gas tank into a container. Do not
use gas that has been stored for more than 60 days.
Dispose of the old gasoline in accordance to Federal,
State, and Local regulations.
2. Start the engine and allow it to run until it stalls. This ensures
that all gasoline has been drained from the carburetor.
3. Allow the engine to cool. Remove the spark plug and put 5
drops of high quality motor oil into the cylinder. Pull the starter
rope slowly to distribute the oil. Reinstall the spark plug.
NOTE: Remove the spark plug and drain all of the oil from the
cylinder before attempting to start the trimmer after
storage.
4. Change the oil, referring to Changing the Oil. Dispose of the
old oil in accordance to Federal, State and Local regulations.
5. Thoroughly clean the unit and inspect for any loose or
damaged parts. Repair or replace damaged parts and tighten
loose screws, nuts or bolts. The unit is ready for storage.
TRANSPORTING
• Allow the engine to cool before transporting.
• Secure the unit while transporting.
• Drain the gas tank before transporting.
• Tighten gas cap before transporting.
0.025 in.
(0.635 mm.)
Fig. 41
Fig. 42
Muffler
Spark Arrestor Screen
Spark Arrestor Cover
Screw
Tab
Slot
WARNING: Do not sand blast, scrape or clean
electrodes. Grit in the engine could damage the cylinder.